The present invention relates to the field of semiconductor technology. Specifically, embodiments of the invention relate to fin type device structures and manufacturing methods.
FIG. 1 is a cross-sectional view illustrating a conventional fin type device (e.g., the FinFET device). The device includes a substrate 102 and a fin structure on the substrate. The fin structure includes a semiconductor layer 104 and a hard mask layer 106 overlying the semiconductor layer. In this conventional structure, the fin structures are separated by an isolation layer 108. Since the insulating layer 108 exists only between parts of the semiconductor layer 104 of the fin, there is no effective isolation in the substrate 102 below the fin structures. As a result, this structure can be susceptible to the problem of leakage current.
The above problems are more pronounced in the bulk semiconductor substrate process. Regarding the DC characteristics of the semiconductor device, devices based on the SOI (Silicon-On-Insulator) substrate and bulk silicon FinFET device of similar device sizes can provide similar on/off current ratio. However, regarding PN junction leakage current and parasitic capacitance of the devices, the difference becomes significant.